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Weaving Calculations

A guide to calculations relating to yarn and cloth and all processes of weaving.It includes reed count, reed width, Maximum EPI for a particular count, weave density, crimp percentage, cloth cover factor etc.

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A guide to calculations relating to yarn and cloth and all processes of weaving.It includes reed count, reed width, Maximum EPI for a particular count, weave density, crimp percentage, cloth cover factor etc.

  1. Reed Count
    It is calculated in stock port system.No. of dents in 2 inches is called Reed Count.
    Reed Count = EPI/(1 + Weft crimp %age)
  2. Reed Width
    Reed Width = Cloth Width *(100+ weft crimp %age)/100
  3. Crimp Percentage
    Crimp %age = {(Warp length – Cloth length)/Cloth Length}* 100
    Crimp %age = {(Warp width – Cloth width)/Cloth width}* 100
  4. Cloth Cover Factor
    1. Cloth Cover Factor = Wp.C.F +Wt.C.F. – {(Wp.C.F. – Wt.C.F)/28}
  5. Maximum EPI for particular count
    1. other design = (Ends /Repeat * 1/Yarn Diametre)/ (No of intersections/repeat+ ends/repeat)
  6. Warp Density

    • = <350
    • Weave Density = 50+{(Warp Density – 100) * F.D – 100} /{(Weft Density – 100)* F.D – 100}
    • Effective Weave Density = W. D x K of loom width x K of Design
      = < 72
Wp / filling – K  Loom Width – K  Weave Design – K
Cotton = 1.00 140 cm – 0.99 Plain1/1 = 1.00
Polyester/Cotton = 1.03 180 cm – 1.00 Twill 1/2 = 0.87
Viscose Filament = 1.17 190 cm – 1.01 Matt, Gabardine 2/2 = 0.82
Polyester Filament = 1.22 220 cm – 1.02 Drill 1/3 = 0.77
250 cm – 1.08 Satin 1/4 = 0.69
330 cm – 1.15
360 cm – 1.20

To change the count and the number of thread/inch, keeping the same denseness of fabric

To change the count without altering the denseness of the fabric
EPI in Exp.cloth = (EPI in exp.Cloth2/EPI in given cloth) * count in given cloth

To change the EPI without altering the denseness of the fabric

Warp requirement to weave the cloth

  • Warp weight in grams /metre = {(Total Ends * 1.0936 * 453.59 * crimp %)/(840 * count)} * wastage %
  • Weft weight in grams /metre ={(R.S. in inches * 453.59 * PPI)/(840 * count)} * wastage % * crimp %
  • Cloth length in metres with given weft weight=( weft weight in kgs * weft count * 1848 * 0.9144)/(PPI * R.S in inches)

For silk and Polyester

  • Warp weight in grams /metre ={(Total Ends * count (Denier) )/9000} * wastage % * crimp %
  • Weft weight in grams /metre = {(R.S in inches * count(Denier)* PPI)/9000}* wastage % * crimp %

Allowance for count in bleached and Dyed fabric

1.Count becomes 4%
2. FinerDyed counts become max 6% Coarser

Fabric Production Calculation

  • Loom Speed = Motor RPM * (Motor Pully Diametre)/(Loom Pully Diametre)
  • Loom Effeciency Percentage = (Actual Production/Calculated Production )* 100
  • Moisture Regain Percentage = {(Yarn Weight – Dried Yarn Weight)/Dried Yarn weight} * 100
  • Moistue Content Percentage = {(Yarn Weight – Dried Yarn Weight)/Yarn weight} * 100
Type of Yarn Moisture Regain % Moisture Content %
Cotton 8.50 7.83
Jute 13.75 12.10
Silk 11.00 9.91
Rayon, Viscose 11.00 9.91
Wool 17.00 14.50
Nylon 4.20 3.78
    • Warp Weight in Kg = (Total Ends * Tape Length in meters)/(1693.6 * Warp Count)
    • Weft Weight in Kg = (R.S in centimetres * cloth length in metres * PPI )/(4301.14 * weft Count)
    • Cloth weight in GSM = {EPI/Warp Cout)+(PPI/Weft count)}* 25.6
    • oz (ounce ) per sq. yard = GSM(Grams per sq. meter)/34

 

  • Material Measurement
    To calculate the length of any rolled fabrics, this formula gives the nearest accuracy.
    L = {0.0655(D-d)(D+d)}/t
    Where L = Length of material (Feet)    t = Thickness of fabrics (inches)
    D = Outside diameter (inches)   d = Inside diameter (inches)
  • The weight of yarn in a cloth
    The weight of cloth manufactured on looms depends upon the weight of yarns in the warp and weft: ends/inch, picks/inch and the weight of size on the warp. Therefore,
    Cloth weight = Weight of warp + Weight of weft + Weight of size (All in-lbs.)
    Whereas Weight of warp in lbs. = (Total No. of Ends * Tape Length in Yards)/(840 * warp yarn count)

Also

6 Comments
  1. Nabeel Jamal says

    what is EPI & PPI

    1. Hafiz Muhammad Rizwan says

      EPI stand for End pick per Inch while PPI stand for Pick Per Inch

  2. Kiruthika says

    Hi,
    How to calculate the leno/bobin yarn consumption for required metres?

  3. Akthar Hussain says

    How to calculate fabric weight per meter using 40 warp,60 weft, reed 58,pick 56,width 48 inches
    Can you please suggest the formula and how to use it

  4. sunil says

    What should be the width of dip fabric meant for tyre manufacturing to be maintained so that after rubber coating EPI will not change
    Regards
    Sunil

  5. tecsilk says

    same crepe silk sarees can be found in http://www.tecsilk.com

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